The present invention relates to a bone-reaming system, and more particularly, to an apparatus and method for cutting select portions of a bone cavity through the use of a removable guide and a motor-driven cutter which both fit substantially within the body of a patient.
Orthopedic surgery has become more and more prevalent in recent years. Some of the more popular surgical procedures in this area involve the total or partial replacement of joints. Often, this is required because of the wearing or degeneration of cartilage within the joint space. As this cartilage typically provides an articulation surface for two adjacent bones, such wearing or degeneration often causes severe pain in a patient. Thus, it has become common place for some or all of the cartilage (and even some bone) to be removed and/or replaced with different orthopedic implants. For example, one joint which is often the subject of one or more surgeries in a patient is the hip. The ball and socket created by the head of the femur and the acetabulum, respectively, tends to wear during the life of a patient. A surgical procedure on this joint typically involves resurfacing or removing the femoral head and resurfacing the acetabulum. In addition, other smaller areas may be targeted during a procedure.
Often the position and orientation of a ball and socket joint, such as the hip or shoulder, within the body make it difficult to effectively operate without an invasive dislocation of the joint. Such a dislocation may irreversibly damage the joint capsule as well as many of the ligaments and tendons attached to and/or around the joint. In addition, the ball and socket portions of a bone are not meant to be dislocated, and so irreparable harm to the bone surfaces of each may also occur from such dislocation.
In some cases, when surgery is necessary on the hip joint, only the acetabulum, and not the femur, may be damaged. If the femoral head and neck are healthy, they require little to no surgical steps and merely become obstacles blocking access to the acetabulum. Even if they are in fact damaged, the remaining femoral structure may also not be useful during operation in or on the acetabulum. For example, when the femur is healthy, it is often removed from the acetabulum before surgery is performed on the socket. In order to avoid major damage to the hip socket, it is possible to move the femoral head a small distance relative to the acetabulum to gain access to the damaged socket. Still, in this situation it is difficult to reach the necessary portions of the acetabulum with any precision because the femoral head is positioned to block the insertion and/or use of a surgical instrument. Penetration into or removal of any portion of the femur in this instance, though it may aid in the surgery on the acetabulum, is not always an option.
Nonetheless, often the need for operation on the acetabulum is accompanied by damage to the femur. As such, a portion of the femur may need to be removed as a part of the same procedure. Although techniques have been developed to use the remaining portion of the femur to aid in the reaming of the acetabulum, the integrity of the femur may not be able to handle such manipulation and force. An example of such a technique is disclosed in U.S. Pat. No. 6,723,102 to Johnson et al. (“Johnson”), which teaches sculpting a bone surface of a first bone while anchoring the bone sculpting tool in an adjacent bone with which the first bone normally articulates. Johnson requires a two-bone system where the bones articulate with one another. The adjacent bone is used to mount the bone sculpting tool, with the figures of Johnson illustrating a complete removal of the femoral head to do so. Even if the femoral head is not removed, a relatively large separation between the ball and socket is necessary to mount such a device to articulate with the first bone. Thus, for surgery on a bone socket which does not require additional medical attention directed to the mating ball, this technique is overly invasive.
Repair of small or focal defects in cartilage is something which also may be desired. The general thought surrounding this technique is to repair only worn portions of cartilage, rather than removing entire cartilage surfaces. Of course, this adds another wrinkle to the preparation of a particular site. In contrast to utilizing relatively large devices to remove an entire cartilage surface, smaller cutters or reamers are desired. To this point such devices have not lent themselves to the preparation of site within a bone cavity, such as a socket of a ball and socket joint.
Therefore, there exists a need for an apparatus for use in a surgical procedure on a bone socket that is minimally invasive and allows for increased precision. A need also exists for an apparatus that may operate on predefined portions of a bone socket without the need for a direct view to the surgical site, and one which can be utilized in connection with repair of focal defects.